// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <jni.h>
#include <vector>

#include "base/android/jni_android.h"
#include "base/android/jni_string.h"
#include "base/android/scoped_java_ref.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "content/browser/android/content_view_statics.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/common/android/address_parser.h"
#include "content/common/view_messages.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_process_host_observer.h"
#include "jni/ContentViewStatics_jni.h"

using base::android::ConvertJavaStringToUTF16;
using base::android::ConvertUTF16ToJavaString;
using base::android::JavaParamRef;
using base::android::ScopedJavaLocalRef;

namespace {

// TODO(pliard): http://crbug.com/235909. Move WebKit shared timer toggling
// functionality out of ContentViewStatistics and not be build on top of
// blink::Platform::SuspendSharedTimer.
// TODO(pliard): http://crbug.com/235912. Add unit tests for WebKit shared timer
// toggling.

// This tracks the renderer processes that received a suspend request. It's
// important on resume to only resume the renderer processes that were actually
// suspended as opposed to all the current renderer processes because the
// suspend calls are refcounted within BlinkPlatformImpl and it expects a
// perfectly matched number of resume calls.
// Note that this class is only accessed from the UI thread.
class SuspendedProcessWatcher : public content::RenderProcessHostObserver {
public:
    // If the process crashes, stop watching the corresponding RenderProcessHost
    // and ensure it doesn't get over-resumed.
    void RenderProcessExited(content::RenderProcessHost* host,
        base::TerminationStatus status,
        int exit_code) override
    {
        StopWatching(host);
    }

    void RenderProcessHostDestroyed(content::RenderProcessHost* host) override
    {
        StopWatching(host);
    }

    // Suspends timers in all current render processes.
    void SuspendWebKitSharedTimers()
    {
        DCHECK(suspended_processes_.empty());

        for (content::RenderProcessHost::iterator i(
                 content::RenderProcessHost::AllHostsIterator());
             !i.IsAtEnd(); i.Advance()) {
            content::RenderProcessHost* host = i.GetCurrentValue();
            host->AddObserver(this);
            host->GetRendererInterface()->SetWebKitSharedTimersSuspended(true);
            suspended_processes_.push_back(host->GetID());
        }
    }

    // Resumes timers in processes that were previously stopped.
    void ResumeWebkitSharedTimers()
    {
        for (std::vector<int>::const_iterator it = suspended_processes_.begin();
             it != suspended_processes_.end(); ++it) {
            content::RenderProcessHost* host = content::RenderProcessHost::FromID(*it);
            DCHECK(host);
            host->RemoveObserver(this);
            host->GetRendererInterface()->SetWebKitSharedTimersSuspended(false);
        }
        suspended_processes_.clear();
    }

private:
    void StopWatching(content::RenderProcessHost* host)
    {
        std::vector<int>::iterator pos = std::find(suspended_processes_.begin(),
            suspended_processes_.end(),
            host->GetID());
        DCHECK(pos != suspended_processes_.end());
        host->RemoveObserver(this);
        suspended_processes_.erase(pos);
    }

    std::vector<int /* RenderProcessHost id */> suspended_processes_;
};

base::LazyInstance<SuspendedProcessWatcher> g_suspended_processes_watcher = LAZY_INSTANCE_INITIALIZER;

} // namespace

// Returns the first substring consisting of the address of a physical location.
static ScopedJavaLocalRef<jstring> FindAddress(
    JNIEnv* env,
    const JavaParamRef<jclass>& clazz,
    const JavaParamRef<jstring>& addr)
{
    base::string16 content_16 = ConvertJavaStringToUTF16(env, addr);
    base::string16 result_16;
    if (content::address_parser::FindAddress(content_16, &result_16))
        return ConvertUTF16ToJavaString(env, result_16);
    return ScopedJavaLocalRef<jstring>();
}

static void SetWebKitSharedTimersSuspended(JNIEnv* env,
    const JavaParamRef<jclass>& obj,
    jboolean suspend)
{
    if (suspend) {
        g_suspended_processes_watcher.Pointer()->SuspendWebKitSharedTimers();
    } else {
        g_suspended_processes_watcher.Pointer()->ResumeWebkitSharedTimers();
    }
}

namespace content {

bool RegisterWebViewStatics(JNIEnv* env)
{
    return RegisterNativesImpl(env);
}

} // namespace content
